The new C63 AMG definitely has the power to justify its billing as the M3 Killer, but there’s apparently no stopping Mercedes-Benz and AMG when it comes to pushing the envelope on performance. That’s because the automaker and its performance wing is still working on a hardcore version of the C63 AMG, the Black Series, and it was recently caught testing in cold weather.

The exterior gets some changes for the Black Series. The spy shots
show wider fender flares, and while they aren’t shown, there will also
be a new front spoiler, an updated rear diffuser, and updated LED
running lights as well as headlamps.

The same engine is available–the 6.2L V8–but it goes for 510
horsepower now, compared to 481 hp on the standard version running on
the P31 Development Package. The same 7-speed AMG Speedshift gearbox is
also inside the Black Series version. Expect a lighter overall weight
for the Black Series.

There have also been reports that a Black Series variant of the C63
AMG Coupe is also coming up. Expect that to be in official news once the
standard version debuts.